Z31 rear conversion

[Draconis]

For IRS models

Okay, so I'm sure many of you are aware of the fact you can swap in Z31 rear trailing arms and stuff into the S12. What is the advantage of this? Well, if you have access to a Turbo Z31 or the MKI Z31 N/A, they allow for vented rear discs. I will get pics of the trailing arm, but I dont see why it would be as needed.

For the MK2 Z31 NA model, it is the exact same as it would be for the S12 IRS setup. I do own a SE so was already stock 5 lug, but knowing that's only dealing with the hubs/brakes, there is virtually not difference between that I am aware of between a SE and non SE. If you have the NA setup, it should for the most part go right into the differential without issue as long as you have a R200. Once you obtain these parts, it is literally direct bolt in. Swap over the brake lines, as they are in the same place as in the S12 and Z31.

[s13eater]

are the z31 calipers wider than the s12 items, as i don't think the s12 calipers would open up wide enough for the z31 discs, so in theory, i could re drill the z31 discs to 4 stud and use them on the s12 arms,but do i need z31 calipers ?

[Draconis]

Ah yes, I did not realize that the point you said wasnt explained well. Thank you. Yes, the calipers are wider to be able to accommodate the thicker rotor since it is vented and not just a single disc. The other thing that will be needed are longer studs/hubs. They are designed so that the rotor slips on and fits into place correctly pushing out the hub just a bit so that everything lines up accordingly. As of the bare minimum of what you need would be Z31 hubs mentioned above and calipers.

I believe CiH would have better pictures since I do know discussing it with him and he obtained a set of rear arms with hubs from a Z31 for a conversion he's planning to do.

[s13eater]

has anyone got a pic of an s12 hub and a z31 hub together ?

[CamInHead]

One interesting point is Z31 turbo and Z31 N/A don't appear to be inter-changeable. When I got my N/A arms we offered up N/A and turbo disks (parts that had been broken by the seller so of known origin). They were the same but the Turbo had deeper back spacing ie, if you lay them face-up, flat on the floor the Turbo was slightly taller.

[s13eater]

could z31 turbo discs and calipers be fitted to the s12 hub though ?, i know i'd have to re drill them for 4 stud fitment, but would i need to space the caliper to centralize the disc ?

[Draconis]

Yes, in theory you could but with the extra spacing for the rotor, it wouldnt work. Reason being, when trying to put on a wheel after putting the rotor on, there are virtually not threads on the lug studs and the caliper would not work due to different spacing of the bridge and the caliper itself needing to fit the extra width of the rotor. I'll get some better pics tomorrow.

[s13eater]

Originally Posted by Draconis

Yes, in theory you could but with the extra spacing for the rotor, it wouldnt work. Reason being, when trying to put on a wheel after putting the rotor on, there are virtually not threads on the lug studs and the caliper would not work due to different spacing of the bridge and the caliper itself needing to fit the extra width of the rotor. I'll get some better pics tomorrow.

ok matey, cheers.

[CamInHead]

presume I need the Z31 specific caliper carriers, as well as the calipers themselves ?

[Draconis]

I do not know to be honest but would not be surprised if the carriers are different. Just the calipers themselves are different.